Energy-efficient thermal management through internal flow reorganization in Schwarz primitive triply periodic minimal surface structures

Triply periodic minimal surface (TPMS) structures are increasingly used for thermal management. However, the conventional Schwarz primitive (SP) geometry allows central flow bypass, limiting convective mixing. This study presents a novel three-circle infilled Schwarz primitive (3CI-SP) architecture that modifies internal flow physics by introducing three infilled circles within a standard SP (Std-SP) design. The thermo-hydraulic performance of the 3CI-SP configurations was evaluated using a steady-state conjugate heat transfer model and computational fluid dynamics (CFD) simulation. The novel 3CI-SP (0.2 mm infilled-circle thickness) was first compared with the Std-SP. Subsequently, further evaluation was conducted by comparing 3CI-SP models with infilled-circle thicknesses ranging from 0.2 to 0.8 mm. The 3CI-SP configuration redistributed internal momentum, resulting in a jetting speed of 25.1 m/s (5.5 times that of Std-SP). Hydraulically, this configuration reduced the inlet pressure by 64% and the total pressure drop by 50.6%, while generating a local negative pressure (-8.9 Pa) that permitted passive localized low-pressure entrainment of the fluid. Thermally, the bulk, maximum heater, and mid-core temperatures decreased by 9.4 K, 6.2 K, and 23.7 K, respectively. Together, these improvements resulted in a 59.0% increase in cooling efficiency and a combined synergy factor of 0.37, indicating greater alignment of momentum and thermal energy transfer than that of Std-SP. However, increasing the wall thickness further caused nonlinear thermal behavior and hydraulic choking. Thus, the 3CI-SP enhances near-wall momentum mixing without introducing additional resistance, making it suitable for compact cold plates and high-heat-flux cooling applications.